US 7,355,997 B2 · Data rate shifting methods and techniques

Abstract

A technique for determining when to change a data rate by determining the cause of packet loss. The technique distinguishes between collision mediated packet loss and poor signal mediated packet loss. Rate shifting to a lower rate is performed after determining poor signals are causing packet loss. After switching to a lower rate, the packet loss rate can be compared to the pre-switch packet loss rate. If the packet loss rate has not improved by shifting to a lower data rate, then the data rate can be shifted to a higher rate. The technique can use a combination of channel response, signal strength, packet loss rate and throughput to determine when to switch data rates. A communication unit can maintain separate histories for each unit it is communicating with and employ a different data rate for each unit.

Claims33

Dependent claims

A method to optimize communications, comprising:

monitoring a performance parameter of a channel, the performance parameter being at least one selected from the group of throughput rate and packet rate loss;
monitoring signal quality;
switching to a lower data rate after the performance parameter indicates a decrease in performance and the signal quality has degraded;
continuing to monitor the performance parameter after switching to the lower data rate;
comparing the performance parameter after switching to the lower data rate with the performance parameter before switching to the lower data rate;
and
switching to a higher date rate after the comparison determines that the performance parameter after switching to the lower data rate did not improve by a predetermined threshold;
wherein the performance parameter that indicates a decrease in performance is at least one of the throughput rate decreasing and the packet loss rate increasing.

5 more elements

An apparatus, comprising:

a channel quality module;
a received signal strength module configured to determine the signal strengths of received signals;
a packet loss module configured to determine packet loss rate;
a rate shifting module coupled to the channel quality module, received signal strength module and the packet loss module;
wherein the rate shifting module is configured to maintain a history of signal quality of a successfully received packet with a data rate;
wherein the rate shifting module is configured to maintain a history of received signal strength of the successfully received packet;
wherein the rate shifting module is configured to maintain a history of packet loss rate;
and
wherein the rate shifting module is configured to switch to a lower data rate responsive to the history of packet loss rate indicating an increase in a rate of packets lost and at least one of a signal quality of a later received successfully received packet is a first predetermined threshold level below the signal quality of the successfully received packet, and a received signal strength of the later received successfully received packet is less than the received signal strength of the successfully received packet by a second predetermined threshold level.

6 more elements

Dependencies are inferred from the claim text.

Data rate shifting methods and techniques

Life of this patent

Data rate shifting methods and techniques

Life of this patent

Abstract

Claims33